Pump of the swash plate type



Jan. 5A, 1943'. l A.n.lla. HASNLl-nf, JR., Erm. 2,307,041

PUMPQOF THE swAsH yPLATE TYPE Filed sept. 2B, 1938 8 Sheets-Sheet 1 I @fw J. B. HAwLEY, JR, TAL PUMP 0F ffl-1E SWAS PIAJATB TYPE Filed sept. 28. 195s 8 Sheets-Sheet 2 Jan- 5, 1943- J. B. HAWLEY, JR., ETAL 2,307,041

PUMP OF' THE SWASH PLATE TYPE 8 sheets-sheet 3` .WWE y T E m EN. E amv WANT NQ M.

Filed Sept. 28, 1938 wLEY JR. NATHE JGHN B- CHRRLES G.

IRVIN NELS I BY ffm?? Jan.5,1943.' .4, B HAWLEY-JR., E'TAL 2,307,041

PUMP OF THE SWASH PLATE TYIPE Filed sept. 28, 195s a sheets-sheet 4 v LM.

f l l w ATTORNEY Jan 5, 1943 J. B. HAWLEYQJR., ETAL 2,307,041

I PUMP OF THE SWASH PLATE TYPE I Filed sept. 2a, 195s a sheets-sheet 5 #if V .S v

- Jan. 5, 1943.

J, B. HAWLEY, JR, Erm. 2,307,041

' PUMP`OF THE SWSH PLATE TYPE l Filed sept. 28:, 195s s snee1s-sneet e Jan. 5, 1943. i J. B. HAWLEY, JR., ETAL 2,307,041

PUMP OF THE SWASH PLATE TYPE JOHN T. GONDEK Jo u H B. HAWLEY JR. CHARLES q. NATHE IRvmG NELSON ATTORNEY Jan. 5, `19415.

J. B. HAWLEY. JR., ETAL PUMP OF THE SWASH PLATE TYPE Filed Sept. 28, 1938 8 Sheets-Sheet 8 ATTORNEY l VPatented Jan. 5, 1943 A John B. Hawley, Jr., Charles G. Nathe, John 'l'. Gondek, and Irving Nelson, Minneapolis. Minn., assignors, by mesne assignments, tov Northern. Pump Company, Minneapolis, Minn., a corporation of Minnesota Appiieaeiop september 28,1938, serial No. 232,112

(ci. 10e- 162) 20 Claims.

This invention relates to a. fluid pump, motor or hydraulic transmission device and particularly to such a device of the kind known as the swash plate type. Such a device comprises a rotating cylinder barrel in which pistons reciprocate, these pistons being movable byI a rotating swash plate ,rotating about the axis of the cylinder barrelbut Vbeing given a wobble'motion by a tilting plate which can be tilted at various angles to the axis of said cylinder barrel.

It is an objectl of this invention to provide such a device with a novel means of rotating the swash plate including a constant velocity type universal joint.v I

It is a'further object of ftheinvention to provide such a device comprising a novel means for driving the swash plate including a constant velocity type universal joint comprising driving and driven members, a driving shaft and a connection between said driving shaft and said driving member permitting angular movement between the axes of said driving member and shaft but' preventing relative movement of said parts perpendicular to the axis of said shaft.

It is another object of the invention to provide such a device comprising a driving shaft, a valve plate and cylinder barrel engaging said valve plate, a swash plate. a tilting plate carrying said swash plate, a universal .joint for driving said swash plate from said shaft comprising a driving member and' a driven member, means receiv-l ing the end thrust of said driving member and resilient means holding said cylinder barrelv against said valve plate and holding said driving member against said means.

" It is still another object of the invention to pro- 1 It is still further an object of the invention to provide such a device comprising a swash plate, a tilting plate carrying said swash plate and a retaining ring or snap ring for holding said swash plate in said tilting plate preferably with locking means for said ring.

It is further an object of this invention to provide such a device having a novel form of housing comprising prismatic members including an end member forming the valve plate, another end member taking the thrust of the swash plate,

eral views and in which:

vide such a device comprising. a driving shaft, a. Y

cylinder barrel. a driving member for said cylinder barrel, said driving member surrounding and being splined to said driving shaft.

It'is still further an object of the invention to provide such a de'vice comprising a valve plate, a cylinder barrel engaging ,said valve plate and a swash plate for operating pistons in said cylinder barrel together with a novel form of pllljnp housing including side plates secured to said valve plate and to an endmember taking the thrust of said swash plate. whereby said side plates are maintained in tension by the reactive forces from said pistons to said swashplate.

It is also an object of the invention to provide such a device having a -novel form of pump housing assembled from parts of regular prismatic shape having flat engaging surfaces capable of being ground.

side plates extending between and connected to said end members together with top and bottom plates having flatsurfaces engaging surfaces on andA secured 'to said end plates whereby said top and/or bottom plate can be removed to permit full inspection of said pump parts without` dis turbing the moving parts of the pump or the adjustment or positioning of said end and side members. Y

These and other objects and advantages of the invention will be fully set forth in the following description' made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the sev- Fig. 1 is a top plan view of the pump, certain parts being broken away and others shown in horizontal section; Y.

2 is a. view partly in side elevation but with elevation but some parts Il"lg.'3isaviewinside others shown in vertical being broken-away and section;-

Fig. 4 is a central snap or retaining ring used; Fig. 5 is aperspective of the universal joint with the driving shaft, some parts being broken away and others shown in vertical section;

Fig. 6 is a vertical section taken on line i-I of Fig. 2 as indicated by the arrow;

Fig. 'l is a perspective-view of a connection block used:

Fig. 8 is a partial centralV vertical section through the valve plate, cylinder barrel and adjacent parts; t Y y Fig. 9 is a face view of the discharging end of the cylinder barrel; Y Fig. 10 is a view similar to. Figi .l showing a modification; Fig. 1l is a view in vertical section taken through the trunnion and axis of the tilting platel and showing a modification;v and y some parts being broken away and others shown in vertical section;

vertical section through a.

view on an enlarged scale Y and connection thereof' y for the cylinder barrel. I'he valve plate is preferpartly in vertical section.

The device described, disclosed and claimed in this invention is an improvement upon that disclosed and claimed in my pending application S. N. 196,225, filed March 16, 1938.

Referring to the drawings a pump or fluid transmission device of the swash plate type is shown comprising avalve plate I5. Such avalve is a well known element in such a device and `comprises oppositely disposed openings I5a. Inlet and discharge conduits I6 are provided and are connected to members I1 and I8 respectively secured to valve plate I5, said members I1 and I8 having annular ribs IIa and Ilia seating in annular grooves I5b in valve plate I5 and engaging gaskets in the bottom of said grooves. Members I1 and I8 may be secured to valve plate l5 in any suitable manner and in the embodiment of the invention disclosed they are shown as secured by headedbolts I1b, which bolts are disposed adjacent the corner of members I1 and I8 and are threaded into valve plate I5. Members I1 and I8 each have central openings therethrough for receiving conduit I6, said openings having enlarged outer'portions in which are disposed packing Amembers I9 engaged by glands 20, which glands are held tightly against said packing members by the headed studs 2I threaded into members I1 and I9. It will be noted that glands 20 diameters of conduits I6. With the described construction it will be seen that conduit I6 may have some angular movement relative to members I1 and I8 and valve plate I5. The valve plate I5 has a recess in its inner face in which is secured a bronze plate I5c forming the bearing .surface ably made of Invar steel. This steel contains nickel and the particular metal used in practice has about 1,425 the coefcient of expansion of regular steel. Bronze plate I5c is welded onto the face of the valve plate I5. Bearing sur'face I5c has therein a substantially annular groove d which is disposed some distance Voutwardly radially of openings I5a. Circumferentially spaced holes or passages I5e extend into valve plate I5 from groove I5d and holes or passages I5f intersect the passages I5e and extend to the inner surs face of valve plate I5 radially outward of bearing surface I5c and of cylinder barrel 22. A

cylinder barrel 22 is provided having a face bearing against the face of bronze portion I5c. Said face of the cylinder barrel has the outlet and inlet openings 22d from the cylinders extending therethrough and some distance radially outward from said openings 22d, said face is provided with a plurality of circumferentially spaced slots 22e which extend outward radially or substantially 35 -porting member 39.

Fig. 12 is a view partly in side elevation and '.vided between this face and bearing surface. Said cylinder barrel 22 has the usual circumferentially spaced cylinders 22c therein with outlet ports 22d adapted to cooperate inthe rotation of said barrel 5 with the openings through the valve plate. Cylinder barrel 22 has a central bore with radially extending recesses therein in which are disposed the head portions 23a oi connecting members 23A having stems 23h received in bushings 24 lil carried in a cylinder barrel driving member 25.

Driving member 25 fits about and is splined to the driving shaft 26, said shaft having quite a number of circumferentially spaced splines therein. The valve plate I5 is centrally recessed 15 at its inner side to receive a ball bearing 21 20 28 are disposed in the cylinders 22e, the same be- -ing illustrated as in the form of `hollow cylinders. Said pistons have connected thereto the connecting rods 29 having ball shaped ends held in the split bearing members 30 disposed Within pistons 2;, 28 and engaged and held therein by the threaded sleeves 3|. Rods 2'8 have their other ends of ball shape and receivedin bearing members 32 held in circumferentially spaced recesses in a swash plate 33 by threaded sleeves 34. Swash plate 33 30 is recessed at its rear end to receive a hard bearhave bores larger in diameter than the outer ing plate 35 which bears against a series of bearing rollers 36 which in turn bear against a hard bearing plate 31 carried in a recess in a tilting plate 88. Rollers 36 are carried in a cage or sup- The bearing plate 35 also has its outer periphery engaging a series of rollers 4II carried in frames 4I,A said rollers bearing against a hard annular bearing plate 42 received in tilting plate 38.l The swash plate 33 is thus rotatably mounted in and carried in tilting plate 38. Said swash plate is provided with a shoulder 33a and a snap ring 43 is adapted to engage said shoulder and a shoulder formed at the inner side of a lip 38a of tilting plate 38. Said ring 43 is adapted vto be'locked in position by having a movable portion or segment 43a which is tapped to receive a headed screw 44 disposed in tilting plate 38 and manipulatable from the outer edge thereof. Swash plate 33 is driven from shaft 26 5o through a universaljoint comprising a driving 5i comprises a yoke 45a formed in the driving member 45 and a' similar yoke 46aformed in the driven member 46, said yokes having non-concen- `tric intersecting ball races whichreceive the steel balls 41. In the rotation of the driving and driven radially to the edge of said cylinder barrel face. .un parts of the joint these ballsroll angularly one- As shown in Fig. 8, the inner ends of slots 22e are so disposed radially as to align with groove I'5d. With .the described construction it will be seen that the oil pumped may pass from the space surrounding cylinder barrel 22 through the passages I5f and I 5e to groove I5d. The oil may then enter the slots 22e and pass outward therethrough to the edge of the cylinder barrel. The said face of .cylinder barrel 22 is made of hard steel half the distance traversed by the yoke. 'The driving member 45 surrounds shaft 26 and at its end opposite that carrying vvoke 45a is provided with a plurality of longitudinally extending tongues 45h shown as'rectangular in plan and vertical cross section.- These tongues are received in recesses 48a formed in a member 48 rigidly secured to ydriving shaft 26.' The tongues 45h and recesses 48a are shown as four in number.

such as case hardened steel and as stated, this 7u The recesses 48a have formed thereinintermediate bearsagainst the bronze bearing surface Lic.A It is desired that there be a very close and perfect iltlbetw/een the face of cylinder barrel 22 and the valve plate bearing surface I5c. It is dethe top and bottom thereof annular slots 48h. Segmental members 49 are received in recesses 48a between the tongues '46h and the walls of said recesses, said segmentalmembers having tongues sired'however. that a lubricating oil lm be pro-JQ 49a projecting from their curved sides and dismember and having its other end'seated in a seated in an annular groove in plate 66 and bearposed in the slots or recesses 46h. With this construction it will be seen that there may be some relative movement between members 46 and 45 to bring their axes at an angle to each other. No movement of said members in a direction per-` pendicular to the 'axis of shaft 26 however, is permitted. Member 46 is thus driven from shaft4 26 to the end of which shown 'as having the keyway 26a will be connected some suitable driving means. Member 45 is driven from member 46 and swash plate 33 ls driven from member 45 through the universal joint or by the balls 41. A' sleeve 56 surrounds shaft 26 and is slidable thereon, the same having one end engaging the reduced end of members 45. The other end of sleeve 50 is received in a member 5I surrounding andslidable on shaft 26. Sleeve 50 abuts against the end of a recess in member 5I and i's prevented 'from rotation by pins 52 in member 5I entering holes therein. The end of the sleeve 50 engaging member 45 is cut away at portions to accom- Y modate movement of the parts. A coiled compression spring 53 surroundsmember 5I having one end engaging the inner side of a iiange, on said i recess in cylinder barrel 22 and engaging a shoulder 22e formed at the bottom of said recess. .Y Spring 53 thus acts to hold cylinder barrel 22 against valve plate I5 and to hold member 45 in position longitudinally of shaft 26.

Member 46 is iournaled in a ball-bearing 54 carried in an end plate 55, which bearing takes the endwisethrust of member 48. A novel form of housing for the pump is provided. Members I5andl 55 form end members and a pair of plates 56 of rectangular form in vertical cross section are provided, the same having at surfaces 56a engaging hat surfaces at the sides of members I5 and 55 respectively.` A key member 51 extends into members I5 and 56, said key connectingthe same and preventing endwise movement of said members. Bolts 56 are also shown extending in the plates 56 and into valve plate I5. Pins 56 which may be dowel pins. connect plates 56 and end plate 55. With the described construction it will be seen that when the reactive-forces 'caused by the pistons 26 in their pumping action act upon the cylinder barrel and swash -Plate, these forces will maintain the plates 56 under tension since they tend to separate 'valve plate I5 and end plate 55. The upper and lower sidesof valve plates 56 are formed with at surfaces which are made flush with the iiat surfaces at the top .and bottom respectively of valve plate Y the presentconstruction eliminates the continuous housing l5 in the structure shown in said pending application with the connections to end members I6 and I1. In the present construction the plates 46 are in effect extended and formed into the plates 56. The present structure is much simpler and has many advantages as will be later pointed out. Top plate 66 has opening 66a substantialLv. centrally thereof which is normally closed by a 63 having an annular rib AII ing on the gasket 64. Plate 66 may receive a closing plug or a connection to an expansion tank.

A member 66 is connected to the outer side of end plate 55 by headedscrews 61, the same having a portion received in the central bore in plate 55 which carries the bearing 54. Shaft l26`ex tends through a central opening in member 66, which opening is enlarged at its outer end to receive packing members 66 engaged by the end of a gland 69 having an annular portionfentering the opening in member 66 and engaging the packing member 66. Gland 66 is pressed against said packing membersby the headed screw 16 passing therethrough and threaded into-member 66. The side plates 56 have openings therein 'for receiving the ball bearing members 1I in which are journaled the trunnions 36h of the tilting platen.

'Said openings in side plates 56 are closed by the plates 12 which will be secured in any suitablev manner. Supporting members 14 shown as in the form of angle members are secured to end members I5 and 55 and act to support the device. The tilting plate 66 has a hub 36e at its rear end which is bored to receive the shank of a fork member 15. This fork member has disposed bev tween the flat sides thereof a block 16 through which extends-a pin 11 received in the sides of fork-.15 and having roller bearings 11a between the same and block 16. Block 16 is connected to a vertically movable rod 16 extending upwardly at one end of the pump through a member 16 which receives packing engaged by a gland 60 secured bythe nutted studs 6I. Rod 16 has a lower rectangular portion 16a having an opening 16h therein between the at sides of which fork 15 is disposed. Block 16 has flat top and bottom sides and these are engaged by bearing sleeves 16h mounted on roller bearings 16e surrounding bearing shafts 16d. Shafts 16d are secured at their ends in the sides of portion 16a. As shown in Fig. l2 sleeves 16h are disposed in the openings 18h. Said rectangular portion 16a isguided in guide members 62 disposed at either side thereof and secured to end member 55 by the headed bolt-s or screws 63. Guide members 62 have portions 62a extending along the sides of rectangular portions engaging the inner side of end member 55. With the present construction it is not necessary to have such a thick end member to' contain the cylindrical bore'. An opening in plate 62 through which member 16 can be inserted isvclosed by'al .plate 55.

. 64 are lprovided having lips 64a projecting over a shoulder formed on swash plate 33. Said lugs 64 are held in place by bolts 65 extending therethrough and threaded into tilting plate 33.

In Fig. 10 a modified form of housing is shown for the parts. Side plates 66 are provided and these extend between the valve plate I5' and the end member 55', which valve plate and end member-are widened to extend to the outer sides of the plates 6I). The ends of side plates 66 may be ground to lit against the adjacent nat and ground surfaces of members I5' and 65'. To hold the parts in assembled Aposition studs 6I extend through members I5' and 55' and inside of side plates 96, said studs being equipped with nuts 62 -at their ends. Side plates Scare connected to membersI5' and 55' by the pins 63 which maybe dowel pins.

In the construction shown in Fig. 1,0V the angle v thereof, all of said studs acting to holdend members I5 and 55 and the side plates 80 in as' sembled position. Otherwise the construction shown in Fig. is the same as already described,

In Fig. 11 a modied form of housing is shown, the same comprising an integral member |00 having a bottom portion |00a and vertical side portions |00b extending at right angles thereto. The housing |00 therefore, forms a three-sided box rectangular in vertical cross section. Said housing willv extend between the valve plate I5 and the end plate 55' shown in Fig. 10 and will have the pins 93 extending thereinto from members I 5' and 55. The side members |00b have' circular and counterb'ored recesses therein disposed about the same horizontal axis and adapted to receive cup members I0| having flanges I0ia seating in the counterbored portions of said recesses and secured therein by the headed bolts |02. Cup members I 0| carry roller bearings |03 in which are journalled the trunnions 38h of the tilting plate 38. The bolts 9| and 95 which connect the housing to end members I5 and 55' are also shown. A cover plate |04 is provided for the top of housing |00 and secured thereto by the headed bolts |05. A cover plate |06 will be secured to the outerside of one side member |00b by the bolts |01. A similar cover plate |08 secured by bolts |09 extends over the cup |0| on the other vertical portion I00b. .Gaskets (not shown) will be provided for plates |06 and |08. Trunnion 38h at one side is shown as having an integral extension 38bb projecting through plate |08 which may be used for the attachmentof an indicator or for some stroking mechanism for controlling the tilting plate 38. An oil seal comprising packing washer I I0 and retaining rings III surrounds trunnion portion 38bb in a recess |08a in plate |08.

46. The swash plate is given a wobble movement .due to its rotation in the tilting plate 38 and the pistons 28 arereciprocated in the cylinders 22c. The pistons move away from valve plate I5 when in alignment with one of the openings therethrough and move toward the valve plate when in alignment with the opening in the opposite side thereof so that suction and discharge are applied to the conduits I6 so that uid is drawn through one of said conduits and discharged through the other. If the device is used as a motor the uid will be forced through one of the conduits I5, will operate the pistons and rotate the swash plate so' that shaft 26 will be driven. The uid will pass out at the other conduit I6. The bearings for the trunnions of tilting plate 38 being carried in the side plates, the trunnions will always be centrally positioned in said bearings and said trunnions are easily accessible for mounting thereon a stroke indicator to show the inclination of the tilting and swash plates or some control member for the tilting plate. Access can be had to the trunnions by simply removing the cover plates l2.

The pump housing is quite simple in construction and comprises prismatic members having ilat surfaces whichvmay be ground to give accurate contact.' In the' construction shown in Figs. 1 to l 3 thesideiplates are in tension and act to hold the end members of the housing Vin position. By using the universal jointv of the constant velocity type, the rotation of the swa yh plate and cylinder barrel are synchronized an they are also synchronized in relation to the rotation of the driving shaft. By this construction the driving shaft can be made integraland extend throughout the pump and through the universal joint. This is very desirable and was not possible with the old type of With the described structure a very rigid houspower will be applied to "drive shaft 26 and driving member 38 will be rotated. This member will rotate driving member of the universal joint comprising members 45 and 46. To take care of a misalignment of the axes of shaft 26 andmember 48 and theA axis of driving member 45 which might be due to faulty assembly if the pump is dismantled and reassembled, the exible connection between parts 48 and 44 is provided which comprises the tongues 45h and the segmental members 49. This exible connection will insure applied Ytof 'driving member` 45. Driving member 45 drives the driven member 46 with a constant velocity and swash plate 33 is driven by member Vthat no stress other than simple torque will be v universal joint previously used in such devices,

` one form of which was shown in said prior application. The present structure is much s im'pler and the parts, particularly the driving shaft, are

' simple and desirable structure. 'I'he separate member is guided in a cylindrical bore in one of the housing members.

The inlet and outlet conduits I6 are alternately hot and cold inthe normal operation due to the high pressure used on the oil or iluid pumped and great strains are set up in these conduits. As stated, these conduits can have motion relativeiy to valve plate I5 without moving said valve plate or exerting a distorting force thereon. The least amount of distortion in this valve plate results in a hydraulic unbalancing of the pump and permits oil pressure getting between the valve plate and cylinder barrel. 'I'his causes the cylinder barrel to move away from or lift off of the valve plate and thus render the pump inemcient and undependable. It will be noted that the top and bottom cover plates may be removed without disturbing the assembled relation of the end members or side plates of thei housing or o'f any of the moving parts. This is a very desirable construction as full inspection of all of the interior of the pump is permitted without disturbing the moving parts of the pump or the adjustment or positioning of the tension members for side plates. The splined or serrated parts connected to the driving member for the cylinder barrel insures a synchrodrive between ma ze ma tend to neat and stick together.

,of the grooves.

asoma the cylinder barrel.

The construction of the engaging portions of the cylinder barrel and valve plate is novel and important. It is necessary to lubricate the engaging bearing surface .of the valve plate and the face of the cylinder barrel. It has been proposed to have radial channels extending through v'the bearing surface on the valve plate outwardly v of groovelid.

In the copending application holes were provided in the bearing surface of the valve plate with channels leading to the bottemporuons thereof. Itisquiteatasktedrinthese holes and with said construction and the construction of the radial channels there is a tendency for dirt and other foreign material incidental to all hydraulic circuits, to become embedded in the relatively soft material of the valve plate. The valve plate bearing surface as above stated, is made from bronze which is relalationof the hydraulic medium or oil outward through the grooves 22e- The oil can enter from around the cylinder barrel through the passages lif, pass through passages I5e to the annular and is being commercially made.

It will, of course, be understood that various changes may be made in the form, details, ar-

rangement and proportions of the parts, without departing from the scope of applicants inven# tion, which generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

l. In a pump construction, a pump housing comprising, end members of normal regular prismatic .shape and substantially rectangular in transverse cross section each having opposite flat sides with plane surfaces capable of being ground, an intermediate portion havingv surfaces engaging said flat surfaces and means connecting said portions with said surfaces in engage'- ment to form a housing substantially rectangular in transverse and longitudinal cross section.

groove lid and thence to the grooves 22e. There is thus a forced circulation through these passages which would result in' a positive flow of the passages ISI and |5e an ingress of oil is at- 1 tained from the space between the pump housing ent construction the desired lubrication canbe had no matter how closely the cylinder barrel face engages the bearing surface ofthe valveJ plate, while with the previously suggested constructions the lubrication became more meillcient as the engagement between the surfaces became more intimate. With the radial slot construction the oil being viscous does not always have a tendency to move inward radially through the slots or grooves. On the other hand due to -the viscosity a nlm may vform at the outer end With the present construction f as above indicated, there is no tendency for im p urities to embed themselves in the bearing surface of the valve plate.

From the above description it will be seen that I have provided a much improved, simpler, compact and eilicient structure of -pump or hydraulic transmission device. The parts are easily made and assembled, and are .very eficient in opera- With the presthe lubricating hydraulic medium. By providing y 2. A pump -or hydraulic transmission device of the swash plate type having in combination, a valve plate having flat sides and fiat top and bottom, a housing comprising side plates having fiat surfaces engaging said flat sides of said valve plate, keys connecting said side plates and valve plate at said surfaces, a cylinder barrel engaging said valve plate, pistons reciprocable in said barrel. a swash plate connected to said pistons, a tilting plate carrying ,said swash plate and an end member vfor said housing secured to said side plates and taking the thrust of said tilting plate whereby the reactive forces on said valve plate and tilting plate from said pistons maintain said side plates under tension. Y

3. The structure set forth in claim 2, said side plates having their edge faces flush with the top and bottom surfaces of said valve plate respectively and with the top and bottom of said end plate respectively and top and bottom cover plates for said housing secured to said valve plate, side plates and end plates.

'4. The structure set forth in claim 2, said side plates having axially aligned openings therein, bearings carried in said openings for receiving the trunnions of said tilting plate and cover plates for said side plates'covering said openings.

5. A pump or hydraulic transmission device of the swash plate type having in combination, a swashplate, a driving shaft, a universal joint of the constantvelocity type connecting said shaft and swash plate and comprising driving and driven members, a member secured to and 'surrounding' said shaft having a plurality of radially extending recesses therein cylindrical in cross section, said driving member having a plurality of tongues rectangular in radial cross section. Certain parts can be easily and quickly removed for inspection without dismantling the tion extending into said recesses respectively, each recess having a groove extending about the 'cylindrical'wall thereof and segmental members ateither side of 'each tongue having their fiat sides disposed against the nat sides of said tongues and tting in said recesses and having ribstting in said grooves whereby the axes of said drivingmember and shaft may be outv of alignment b ut radial movement of said driving member is prevented.

6. A pump or hydraulic transmission device of theswash plate type having in combination, a'valve plate having `a at bearing surface with oppositelyy disposed inlet and exhaust passages extending through said surface and having an annular groove therein radially outward of said device has been amply demonstrated in actual practice, found to be very successful and efficient openings, passages leading from said groove through said plate and having outlets at the inner side of said plate radially beyond said bearing surface, a cylinder barrel having a face engaging said bearing surface through which the inlet and outlet openings from the cylinders in said barrel extend, said face having grooves extending outwardly therein beyond said inlet and outlet openings, the inner portions of which align with said groove in said bearing surface.

7. A pump or hydraulic transmission device of the swash plate type having in combination, a valve plate having a flat bearing surface with oppositely disposed inlet and exhaust passages extending through said surface having an annular groove therein radially outward of said openings, a cylinder barrel having a face engagcomprising driving and driven members, said shaft extending in'tegrally through said swash plate, a member for driving said universal joint rigidly secured to said shaft and having a plurality of radially extending recesses therein about said shaft, the driving member of said universal joint having portions extending into said recesses and means in said recesses connecting said portions to said last mentioned member and permitting angular movement between the axes of said member and the driving member of said universal joint but preventing movement ing said bearing surface through which the openings into the cylinders' in said barrel extend, said face having circumferentially spaced outwardly extending grooves therein radially outward of said last mentioned openings and extending inwardly to communicate with said annular groove and means for supplying oil to said annular groove whereby the rotation of A said cylinder barrel` will cause a circulation of oil radially outward through said grooves therein and said face and bearing surface will be lubricated.

8. A pump or hydraulic transmission device'of `of the swash type having a frame, a swash plate and a tilting plate carrying the swash plate for operating pistons in a cylinder barrel, the combination of a shaft journaled in said frame, and a universal joint of the constant velocity type connecting said shaft and said swash plate and comprising driving and driven members, said shaft extending integrally through said swash plate, said shaft and driving member of said universal joint having respectively circumferentially spaced intertting tongues and sockets constructed and arranged to be movable for eliminating strains other than simple torque from said joint, whereby said driving and driven members may maintain their alined positions.

10. In a pump or hydraulic transmission device of the swash type having a frame, a swash plate and a tilting plate carrying the swash plate for operating pistons in a cylinder barrel, the

combination of a shaft journaled in said frame, and a universal joint of the constant velocity type connecting said shaft and said swash plate and comprising driving and driven members, said shaft extending -integrally through said swash plate, said shaft and driven member of said universal joint having respectively circumferentially spaced intertting tongues and sockets constructed and arranged to be'permitting relative angular movement of the axes of said parts but preventing radial movement thereof. Y

1l. In a pump or hydraulic transmission device of the swash type having a frame, a swash plate and a tilting plate carrying the swash plate for `operating pistons in a cylinder barrel, the combination cfa shaft journaled in said frame, a universal joint of the constant velocity type connecting said shaft and said swash plate and perpendicular to said axes.

12.'In a pump or hydraulic transmission device of the swash plate type having a frame, a driving shaft journaled in said frame, a swash plate surrounding said shaft and a cylinder barrel surrounding and driven from said shaft, `the combination of a universal joint of the`constant velocity type connecting said shaft and swash plate, said joint comprising driving and driven members, said driving member surrounding said shaft and being movable longitudinally of said shaft, a sleeve longitudinally movable on and surrounding said shaft having one end engaging saiddriving member and resilient means engaging said cylinder barrel for pressing said sleeve against said driving member and for holding said driving member and cylinder barrel in position. f

13. In a pump or hydraulic transmission device of the swash plate type having a frame, a driving shaft journaled in said frame, a swash plate surrounding said 'shaft and a cylinder barrel surrounding and driven from said shaft, the combination of a universal joint of the constant velocity type connecting said shaft and swash plate, said joint comprising driving and driven -duits secured to said valve plate for conducting fluid therethrough and to said cylinder barrel and means securing said conduits to said valve plate including members relative to which said conduits may move angularly so that angular movement of said conduitsl is permitted relatively -to said valve plate whereby stresses occurring in said conduits and moving the same will not move said valve plate relatively to said cylinder barrel to permit the escape of fluid between said valve plate and cylinder barrel.

15. The structure set forth in claim 14, said means including yielding packing means for said conduits.

16. In a pump or hydraulic transmission device having a rotatable swash plate, a tilting plate in which said swash plate is carried having laterally extending trunnions about which itis movable to various angles to give a variable wobble motion to said swash plate, the combination of a housing in which said trunnions are jourtilting the same having a lower guiding portion and separate guide members bolted to said end plate and partially embracing said guiding portion for guiding the same -in its vertical movey ment.

17. The structure set forth in claim 16, said guiding portion being rectangular in cross section and engaging said end plate at one side, said guiding members having portions engaging the opposite side of said rectangular portion.

18. In a pump or hydraulic transmission deviceof the swash plate type having a barrel with cylinders therein, a tilting plate having a fiat annular surface adjacent said barrel, a swash plate carried in said tilting plate having an annular shoulder with a surface in a plane parallel to said surface, a retaining ring within said tilting plate engaging said shoulder for preventing said swash plate from moving out of said tilting plate when said pump is starting up or running with negative pressure in said cylinders and means in said tilting plate for holding said ring in place, said means being disposed wholly at a side of said annular surface remote from said barrel.

19. The structure set forth in claim 18, said ring having a radially removable dove-tailed section therein and said last mentioned means comprising a screw extending radially in said tilting plate and threaded into said segment.

20. In a pump or hydraulic transmission device of the swash plate type having a frame, a swash plate and a tilting plate carrying the swash plate for operating pistons in a cylinder barrel, the, combination of a shaft journaled in said frame, a universal joint of the constant velocity type connecting said shaft and said swash plate comprising driving and driven members having races, balls movable in said races and means for rotating said driving member from said shaft comprising a second member secured to said shaft, said second member and driving member having relative angular movement but no relative circumferential movement whereby only simple torque strains willbe transmitted to said joint and undue strains will not be placed on said races and balls.

JOHN B. HAWLEY, JR. CHARLES G. NATHE. JOHN T. GONDEK. IRVING NELSON. 

